The Marin Humane Society seized two more horses from a rural breeding operation in an ongoing investigation of potential animal neglect, a spokeswoman said Monday.

Investigators took two mares that were "thin and suffering from neglect" from the ranch, which is off Chileno Valley Road just inside the Marin County line, said shelter spokeswoman Carrie Harrington. The mares are under medical observation, she said.

On Dec. 27, animal welfare officers took an injured stallion and an allegedly malnourished mare from the property. The Marin Humane Society said some two dozen horses were being subjected to serious neglect, injuries, unsafe and inhumane living conditions."

The breeder, Jill Burnell of Gray Fox Farms LLC, denies any animal neglect or abuse, and she plans to petition Marin Superior Court to get the horses back, said her lawyer, Maggie Weems.

Weems, whose office is in Fairfax, said she also represents a Georgia woman who bought the stallion and was waiting for it to be shipped before it was injured and confiscated. According to Weems, the stallion was hurt not from abuse or neglect, but in a fight with another stallion.

"The animals were tended to immediately," she said.

Burnell said she and her business are being unfairly treated by both the Marin Humane Society and a "tremendously hot" stream of negative comments on an equestrian news site, The Chronicle of the Horse.

"I'm just very disappointed in the way this is unfolding," said Weems, who is involved in the local horsing community.

Gray Fox Farms was located southern Sonoma County until earlier this year, when it moved to the current site.